Epitaxial growth is a popular method of creating a crystalline region on a semiconductor substrate. However, formation of semiconductor structures in unwanted regions of the semiconductor substrate is undesirable.
Selective epitaxial growth (SEG) is used for creating a crystalline region on targeted areas of the semiconductor substrate. For a selective epitaxial growth, a semiconductor substrate is covered with a masking material, exposing certain areas of the underlying substrate. For such semiconductor substrate, the epitaxial growth occurs mainly on the exposed areas of the semiconductor substrate, and less so on the masking material.
However, certain semiconductor materials, when epitaxially grown, form non-flat top surfaces. On the other hand, many semiconductor devices require a flat surface to build additional semiconductor structures thereon, which, in turn, requires additional operations to planarize the semiconductor structures with non-flat top surfaces. Such additional operations can be time-consuming and costly, and may cause damages to the semiconductor structures.